Dynamo-electric machine provided with commutating pole-pieces.



0. H. SMOOT. DYNAMO ELEGTRIG MACHINE PROVIDED WITH GOMMUTATING POLE PIECES.

APPLICATION EILED SEPT.5,1911. I 1,1 14,405, Patented Oct. 20, 1914.

I3 Z113 i M -14 lFi-El I 9 F 19. I.

' 23 PVlT/YESSES: m INVENTOR.

UNITED STATES PATENT OFFICE.

CHARLES HEAD snow, or HOLLIS, NEW You; assrono'n TO RATEAU BATTU smoo'r co umn, OF NEW YORK, N. Y.

nYNaMmE Ec'raIc MAcHiN'E PROVIDED ma COMMU'I'ATING POLE-PIECES.

To all whom it may concern:

Be it known that I, CHARLES HEAD Srioo'r,

a citizen .of the United States, residin in Hollis, borough of Queens,.county and S tate of New .York, have invented certain newand useful Improvements in Dynamo-Electric.

Machines Provided with Gommutatin Pole- Pieces, of which the following is a ful complete, concise, and exact description, reference being had to the accompanying drawin forming a art of this specification.

he object 0 my resent inventionis toprovide an improve construction and arrangement of the auxiliary or commutatmg pole pieces employed in the commutator type of dlrect oralternating current electrical motors and dynamos, whereby am enabled to very exactly compensate for the demagnetizing action ofthe armature, and to communicate to the armature within the'com-' mutating zone a magnetic flux which is just suflicient to neutralize the effect of the armature coils, and thereby effect sparkless commutation.

Heretofore it has been usual to adjust the magnetizing eflect of a commutating pole piece by a justing the amount of current passing through the commutating pole wmdmg by the use of a shunt which by passes a certain portion of the current flowing from the armature. since variations in temperature of the winding and shunt cause relative variations in the resistance of the winding and shunt with the result that it is impossible to keep the fraction of the total current flowing through the winding constant. a

In carrying out my invention I 'form each commutating pole with an air gap, and make provisions for securing the variable amounts of magnetic material in said air gap where-' by the magnetic reluctances of I e commutating pole piece may be varied. In my apparatus therefore the entire current may always be passed through the commutating pole windings, since desired variations in the magnetic effect of these windings may be obtained by adjusting the magnetic reluctances of the commutating poles.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to andforming a part of this specification; for a better understanding of my invention, however, reference should be had to the accom- Specification of Letters Patent. Application filed September 5, 1911. Serial No. 647,744.

This method is not accurate Patented'OcttZO, 1914.

panying drawings and descriptive matter in which I have illustrated and descrlbed a preferred embodiment of my lllVQlltlOlL,

-' Ofthedra'wings: Figure 1 is an elevation .with parts removed and in section of a dy namo electric machine; and Fig. 2 is a radial section through one of the coinmutating pole pieces and-the-field ring of Fig; 1.

In the direct current dynamo shown by thedrawings, 1 represents the armature formed with the usual slots 2 to receive the armature conductors 3, of which those filling one only of the slots 2 are shown in the drawings- The main pole pieces 4, 5, 6 and. 7 are provided with the usual windings forenergizing the main magnetic circuit or circuits'of the machine. The commutating pole pieces 8, 9, 10 and 11 which are arranged one between each adjacent pair of main pole pieces are all like. In the constructlon'shown by the drawings the commutating pole pieces each comprises a body portiono f, magnetic material which is surrounded by an energizing winding 12.- The body portion of each commutating pole piece is secured to a plate like piece of magnetic material 18 by the screws 14 formed of non -magnetic material. These screws pass throughspacers 16 and 17 of non-magnetic material which separate the pole piece body from the plate 18, which is secured to the magnetic yoke or field ring 1570f the machine by the bolts 19. The spacers 16 and 17 are spaced apart to provide a space 13 in which magnetic plates 20 may be inserted to vary the reluctance of the air gap between the pole piece body and the plate 18. As shown, these plates 20 are clamped against the plate 18 by the bolts 21.

22 represents the insulation material supporting the winding 12. I

The pole tip or face 23 of each commutating pole piece is secured to the body of the pole piece screws 24. WVith this construction the air gap in each commutating pole piece may be adjusted by the removal of one or both of the gap adjusting plates 20, or the insertion of additional plates, or plates of different thicknesses. Furthermore these plates may be readily changed after themachine is completely assembled and operated so that the air gap in each commutating pole may be adjusted in the manner which the actual operation of the machine shows is necessary to obtain perfect commu- 110 ILL means for securing said pole piece to said ;yoke with an alr gap between the pole piece a commutating pole piece, a winding therefor through which substantially all of the current generated by the machine passes, and

and armature, and with an air gap between the pole piece and yoke, said last mentioned air gap being shaped and disposed to receive lammations of magnetic material whereby the efiective length of said air gap may be adjusted.

2. In a commutating dynamo electric machine the combination with the magnetic oke of the machine and its main polar proections of commutating polar portions in- "terposed between said main polar portion and secured to said yoke, winding surroundmg said commutatmg polar portions, and prov1s1ons whereby the magnetic reluctance of said commutating adjusted without i 3. In a commutating dynamo electric ma-.

chine the combination with the magnetic yoke of the machine of a commutating pole piece attached to said yoke and formed with an air gap and comprising provisions for securing variable amounts of magnetic material in the said air gap whereby the reluctance of the said pole piece may be adjusted.

4:- In a commutating dynamo electric machine the combination with the armature, magnetic yoke, and main poles secured to said yoke, of'commutating pole pieces separated from said armature by air gaps, nonmagnetic means for securing each commutating 'pole to said yoke with an air gap between the yoke and each commutating pole, means for detachably securing a variable number of plates of magnetic material in the air gaps between the commutating poles and yoke and windings surrounding said commutating poles.

In witness whereof, I hereunto subscribe my name.

' CHARLES HEAD SMOOT. Witnesses:

L. BATTU, C. D. BROOKS.

Copies of this patent may be obtained fer five cents each, by addressing the Commissioner or Patents, Washington, D. G.

polar portions may be 

